Aromatic compounds, processes for their preparation and their use in perfumery

ABSTRACT

Compounds consisting of indan derivatives of the formula: Wherein X or Y represents an aldehyde or an acetal group and the other represents a hydrogen, and R represents a hydrogen or a methyl group and the t-butyl group is at the 5 or 6 position of the phenyl ring. Where these compounds are useful as perfuming ingredients for the preparation of perfuming compositions and perfumed articles to which they impart floral odor notes.

This is a division of application Ser. No. 08/439,754, filed May 12,1995, now U.S. Pat. No. 5,552,379.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to the field of perfumery. It concerns, inparticular, novel aromatic compounds which are useful as perfumingingredients, of formula ##STR2## wherein symbol X represents a --CHOgroup or a group of formula ##STR3## in which symbols R', takenseparately, represent each a C₁ to C₄, linear or branched, saturated orunsaturated alkyl radical, or taken together represent a substituted orunsubstituted C₂ to C₄ alkylene radical; symbol R² represents a hydrogenatom or a methyl radical; and R¹ and R³ are different and represent eacha hydrogen atom or a methyl radical;

or of formula b. ##STR4## wherein the tert-butyl radical is located inposition 5 or 6 of the aromatic ring and, either Y represents hydrogenand X and R² have the meaning indicated above, or X and R² representeach a hydrogen atom and Y represents a --CH₂ CHO group or a group offormula ##STR5## in which R' is defined as in a.; or of formula c.##STR6## wherein X and R² have the meaning indicated in formula (Ia) andR represents a hydrogen atom or a methyl radical, the groups R beingidentical or different.

The invention also provides a method to confer, improve, enhance ormodify the odor properties of a perfuming composition or a perfumedarticle, which method comprises adding to said composition or article afragrance effective amount of a compound as mentioned above.

The invention further relates to the perfume compositions and perfumedarticles which contain the above-mentioned compounds.

The invention also relates to a process for the preparation of acompound of formula ##STR7## wherein symbols X and R² have the meaningindicated in formula (Ia), or of formula ##STR8## such as defined inclaim 1, which process comprises: a. hydrolyzing, by means of an acid,an enol-ester of formula ##STR9## or respectively of formula ##STR10##in which formulae R and R² have the meaning indicated above and symbolR⁴ represents a C₁ to C₃ alkyl radical, to form the correspondingaldehyde (I'a), respectively (Ic); and

b. where applicable, acetalyzing, in a generally known manner, saidaldehyde thus formed to obtain the corresponding acetal.

The invention also provides a process for the preparation of a compoundof formula ##STR11## wherein X and R² are defined as in formula (Ia),which process comprises:

a. catalytically hydrogenating, in an inert organic solvent, an aldehydeof formula ##STR12## wherein R² has the meaning indicated above, to formthe corresponding aldehyde (I"a); and

b. where applicable, acetalyzing, in a generally known manner, saidaldehyde (I"a) thus formed to obtain the corresponding acetal.

Yet another object of the invention is a process for the preparation ofa compound of formula ##STR13## wherein the tert-butyl radical islocated in position 5 or 6 of the aromatic ring and either Y representshydrogen and X and R² are defined as in formula (Ia), or X and R²represent hydrogen and Y represents a --CH₂ CHO or a group of formula##STR14## in which R' has the meaning indicated in formula (Ia), whichprocess comprises:

a. treating with an oxidizing agent an alcohol of formula ##STR15## toform the corresponding aldehyde (Ib); b. where applicable, methylating,in a generally known manner, the aldehyde obtained in a. whichcorresponds to alcohol (IVb) to form an aldehyde (Ib) of formula##STR16## and c. where applicable, acetalizing, in a generally knownmanner, said aldehyde (Ib) to form the corresponding acetal.

Finally, the compounds of formulae (II), (III) and (IV), used asstarting products in these processes, are also the object of theinvention.

BACKGROUND OF THE INVENTION

As is apparent from the following Table, there are a variety of priorknown compounds whose structure is dose to that of compounds (Ia), someof which have met with commercial success. Furthermore, several of theseknown compounds are described in the reference textbook of S. Arctander,Perfume and Flavor Chemicals, Montclair, N.J., U.S.A. (1969) and this isindicated in the table.

                                      TABLE                                       __________________________________________________________________________    Compounds         Odor       Reference                                        __________________________________________________________________________     ##STR17##        very strong, floral  lily of the valley                                                  Naarden Int.-  product sheet                      ##STR18##        floral, green,  lime-blossom                                                             Arctander 496                                     ##STR19##        floral, green,  cucumber, melon, lime-                                                   Arctander 758                                     ##STR20##        floral, sweet, green,  fruity                                                            Arctander 2741                                    ##STR21##        floral, sweet, spicy                                                                     Arctander 2073                                    ##STR22##        floral, green, lily of  the valley                                                       NL 7905175                                        ##STR23##        fresh, floral, fruity,  melon, lily of the  valley,                           lime-blossom                                                                             US 4'910'346                                     __________________________________________________________________________

In spite of the abundance of known products of this type, the researchactivity in this field remains unflagging, namely with the aim ofdiscovering compounds which have a wider variety of odor nuances andalso compounds which have an enhanced stability in compositions,compared to that of the known compounds. It is in fact of generalknowledge that these prior art aldehydes are very readily air-oxidizedto form the corresponding acids, which are either odorless or possessdisagreable odors, but, either way, no longer display the desiredolfactive characters.

DETAILED DESCRIPTION OF THE INVENTION

We have now surprisingly discovered that the above-mentioned compounds(Ia, b, c) possess very useful odor properties, which are also distinctfrom those of the prior art compounds, and that they are alsoadvantageous from the point of view of stability against oxidation andfragrance tenacity. Namely, it has been established that certainpreferred compounds of the invention are able to advantageously replace,in their typical applications, their known analogues, i.e.-(4tert-butyl-1-phenyl)-2-methylpropanal, or LILIAL® (origin:Givaudan-Roure, Vernier, Switzerland), and3-(4-tert-butyl-1-phenyl)propanal, or BOURGEONAL® (origin: Naarden Intl,Holland), and that they could be far more stable and tenacious than thelatter when used for example in detergents and fabric softeners.

Thus, amongst the compounds of the invention, preferred products include3-(5-tert-butyl-2-methyl-1-phenyl)propanal which develops a verypowerful floral, green note, the character of which is reminiscent ofthe odor of thyme. Its chain-methylated homologue, i.e.2-(5-tert-butyl-2-methylbenzyl)propanal, possesses a floral and verypowerful lily of the valley type note, also of excellent tenacity.

Curiously, 3-(3-tert-butyl-5-methylphenyl)propanal and3-(3-tert-butyl-5-methylphenyl)-2-methylpropanal, which are isomers ofthe above two compounds of the invention, develop entirely distinctodors, the first mentioned compound having a rooty, earthy odor, of thevetyver type, with a very powerful floral, green bottom note, and thesecond developing a prized ozone type odor.

Amongst the bicyclic compounds of formulae (Ib,c), preferred productsinclude 5-tert-butyl-2-indancarbaldehyde, the odor of which isparticularly strong and tenacious, floral, green, reminiscent of theodor of BOURGEONAL®, also possessing a watery-ozone nuance of greatvalue. As for 5-tert-butyl-2-methyl-2-indancarbaldehyde, having afurther methyl radical, it develops a very different fragrance, with ametallic, aldehydic, green character, also watery and vaguely phenolic.

Another compound preferred by the perfumers is3-(3,3-dimethyl-5-indanyl)propanal, which has a green, ozone, floral,aldehydic odor, of rare strength and also very tenacious. Its odor noteis instantly reminiscent of the fragrance of freshly washed, cleanlinen. As directly obtained from the synthesis described further on,this compound may be accompanied of a minor amount of its isomer3-(1,1-dimethyl-5-indanyl)propanal, which develops a similar odor, suchthat the mixtures of these two compounds have an olfactive character ofthe type here-above described.

Yet another preferred compound of the invention is6-tert-butyl-1-indanacetaldehyde, the odor of which resembles that of5-tert-butyl-2-indancarbaldehyde cited above, while possessing a morepronounced cresylic note and a greener, more anisic nuance, also lessaldehydic-lily of the valley than the latter.

One can still cite, as a preferred compound, 3-(5indanyl)propanal, whichdevelops an aldehydic odor of the BOURGEONAL® type, remarkably powerfuland with a citrus bottom note. This compound can also be used to thesame effect in admixture with its isomer 3-(4-indanyl)propanal.

It is apparent from the preceding considerations that the compounds ofthe invention bring a new and varied range of odor nuances to theperfumers' palette, while retaining certain of the odor characters mostappreciated in the prior art compounds of similar structure cited in theTable above.

On the other hand, as shown in the examples presented further on, it hasbeen discovered that the compounds (Ia), whose structure is closer tothat of the prior art products, turn out to be far more stable againstoxidation than the latter and possess far more tenacious fragrances,which renders their use in particularly agressive media such asdetergents and household products distinctly advantageous.

This result of our studies was all the more unexpected in that, in spiteof the large number of new compounds prepared during these studies, somefifty or more, by varying the nature and the position of the substituentgroups and the nature of the functional group (ester, ether and nitrilederivatives having also been prepared), few really attracted theperfumers' interest, and amongst which compounds (Ia, b, c) showedexceptional odor properties and, particularly those wherein R²represents a hydrogen atom, better stability than the known compounds.These advantageous properties appeared as a result of ingeniousolfactive evaluations carried out by panels of expert perfumers, whodiscovered with surprise the superiority of the odor properties of thecompounds of the invention, which superiority was quite clear not onlyon smelling strip evaluations of each pure product or of compositionscontaining it, but also when said product was applied for perfumingdetergents and fabric softeners in particular.

The compounds of the invention can be used with equal advantage in bothfine and technical perfumery and, as a result of their odor qualities,their use is far more general than that of the known compounds, namelyknown p-tert-butyl-α-methyl-hydrocinnamic aldehyde. They are useful toprepare perfuming bases and perfumes and to perfume a variety ofconsumer products such as soaps, bath and shower gels, shampoos andother hair-care products, cosmetic preparations and body or airdeodorants. In addition, as a result of the strength and tenacity oftheir odor note, 5-tert-butyl-2-indancarbaldehyde and3-(3,3-dimethyl-5-indanyl)propanal in particular revealed themselves tobe of an extremely advantageous use for perfuming detergents and fabricsofteners. Household products can also be perfumed by means of compounds(Ia, b, c).

In these applications, the compounds of the invention can be used in awide range of concentrations. One can cite, by way of example,concentrations of the order of 5 to 10%, even 15 or 20% by weight,relative to the weight of the composition into which they areincorporated.

It is clear however that such values are only indicative, since theconcentrations of compound (I) are dependent on the olfactive effectthat is desired to achieve, as well as on the nature of the product tobe perfumed. In addition, they are also a function of the nature of theother ingredients present in a given composition whenever compounds (I)are used in admixture with solvents, adjuvants and perfumingco-ingredients of current use in perfumery, examples of which can befound in reference textbooks such as the work of S. Arctander, Perfume &Flavor Chemicals, Montclair, N.J., U.S.A. (1969).

Concentration values well below those cited above, of the order of 0.1to 0.5% by weight, relative to the weight of the composition into whichthey are incorporated, will generally be used when compounds (I) areemployed for perfuming the various consumer products mentioned above.

The invention also relates to a process for the preparation of acompound of formula ##STR24## wherein symbols X and R² have the meaningindicated in formula (Ia), or of formula ##STR25## as previouslydefined, which process comprises: a. hydrolyzing, by means of an acid,an enol-ester of formula ##STR26## or respectively of formula ##STR27##in which formulae R and R² have the meaning indicated above and symbolR⁴ represents a C₁ to C₃ alkyl radical, to form the correspondingaldehyde (I'a), respectively (Ic); and

b. where applicable, acetalyzing, in a generally known manner, saidaldehyde thus formed to obtain the corresponding acetal.

The hydrolysis of esters (IIa) and (IIc) is carried out underconventional conditions, by means of any acid of current use in thistype of reactions [see for example, J. March, Advanced OrganicChemistry, 3rd ed., section 0-11, John Wiley & Sons, U.S.A. (1985)]. Thedetailed conditions of these reactions are described in the preparationexamples presented further on. Compounds of formula (IIa) or (IIc)wherein R⁴ represents a methyl radical are preferably used.

The latter are novel compounds which are also the object of theinvention. Compounds (IIa) can be prepared from benzene derivatives ofcommercial origin and compounds (IIc) starting from the appropriateindane [see M. T. Bogert and al., J. Amer. Chem. Soc. 56, 185 (1934); S.T. Bright and al., J. Org. Chem. 55, 1338 (1990)] via condensation withan unsaturated diacetate [see, for example, I. Scriabine, Bull. Soc.Chim. France 1961, 1194; N. E. Kologrivova and al., C.A. 78, 88513p(1973)]. ##STR28##

The conditions of these condensation reactions are described in detailin the examples presented further on.

The invention also relates to a process for the preparation of acompound of formula ##STR29## wherein X and R² are defined as in formula(Ia), which process comprises:

a. catalytically hydrogenating, in an inert organic solvent, an aldehydeof formula ##STR30## wherein R² has the meaning indicated above, to formthe corresponding aldehyde (I"a); and

b. where applicable, acetalyzing, in a generally known manner, saidaldehyde (I"a) thus formed to obtain the corresponding acetal.

The hydrogenation reaction takes place in the presence of a catalystsuch as Pd-C, under classical conditions, described further on in adetailed manner.

The starting products of formula (III) are novel compounds, preparedfrom 5-tert-butyl-1,3-dimethylbenzene, according to the followingscheme: ##STR31##

We observed that the reaction of condensation of the intermediate acetal[step b), see for example, H. von der Bruggen and al., J. Org. Chem.1983, 2920 and refs. there-cited] was best carried out in the presenceof zinc chloride and phosphoric acid.

The reactions represented in this scheme are described in further detailin the examples presented further on.

If desired, the aldehydes of formula (I'a) and (I"a), obtained asdescribed above, can be converted into the corresponding acetals by wayof methods well-known to the skilled person, for example by reactingsaid aldehydes with appropriate alcohols or diols, in the presence of anacidic catalyst [see for example, J. March, Advanced Organic Chemistry,section 6-6, 3rd ed., John Wiley & Sons, U.S.A. (1985)]. The detailedconditions of these acetalyzation reactions are described in thepreparation examples appearing further on.

The bicyclic compounds of formula (Ib) according to the invention areprepared following an original process which comprises:

a. treating with an oxidizing agent an alcohol of formula ##STR32## toform the corresponding aldehyde (Ib); b. where applicable, methylating,in a generally known manner, the aldehyde obtained in a. whichcorresponds to alcohol (IVb) to form an aldehyde (Ib) of formula##STR33## and c. where applicable, acetalizing, in a generally knownmanner, said aldehyde (Ib) to form the corresponding acetal.

The reactions of oxidation of compounds (IV) take place underconventional conditions, for example by means of pyridiniumchlorochromate (PCC) as oxidizing agent.

The formula (IV) alcohols are novel compounds which can be prepared in aclassical manner, as represented hereafter for the compounds (IV) havingthe tert-butyl radical in position 5 of the aromatic ring. ##STR34##

These reactions are described in further detail in the preparationexamples presented further on.

The aldehydes (Ib) according to the invention can then be converted intothe corresponding acetals as described above.

The invention will now be described in greater detail by way of thefollowing examples, wherein the temperatures are indicated in degreesCelsius and the abbreviations have the usual meaning in the art.

EXAMPLE 1

Preparation of 3-(5-tert-butyl-2-methyl-1-phenyl)propanal

To a solution of 3-(5-tert-butyl-2-methyl-1-phenyl)-1-propenyl acetate(mixture Z/E˜1:10; 0.68 g, 2.7 mmole) in tetrahydrofuran (THF, 8 ml),kept under stirring, there was added aq. 25% H₂ SO₄ (2 ml) and themixture was heated to reflux (65°) during 2 h. It was then diluted withether and brine, the organic phase was washed with sat. NaHCO₃ andbrine, dried over Na₂ SO₄ and concentrated (0.62 g). After bulb-to-bulbdistillation (oven temp. 160°/0.5×10² Pa), there was obtained3-(5-tert-butyl-2-methyl-1-phenyl)propanal as a colorless oil (0.54 g,purity 96%, yield 96%).

IR(neat): 2950, 2890, 2850, 2700, 1720, 1495, 1450, 1355, 1265, 1130,820 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.85(t, J=1, 1H); 7.16(dd, J₁ =8, J₂ =2, 1H);7.14 (broad s, 1H); 7.09(d, J=8, 1H); 2.94(t, J=8, 2H); 2.74(t, J=8,2H); 2.28(s, 3H); 1.30(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 201.6(d); 149.8(s); 138.0(s); 132.8(s);130.2(d); 125.7(d); 123.4(d); 44.3(t); 34.3(s); 31.4(3q); 25.9(t);18.7(q) δ ppm.

MS: 204(M⁺, 16), 189(94), 171(9), 145(100), 128(16), 115(27), 105(18),91(25), 77(13), 57(11), 41(13).

Odor: described above.

The starting 3-(5-tert-butyl-2-methyl-1-phenyl)-1-propenyl acetate wasprepared as follows.

To a stirred solution of 4-tert-butyl-toluene (Fluka, purity 95%, 18.1ml, 10 mmole) in CH₂ Cl₂ (10 ml), at room temperature, there was addedTiCl₄ (Fluka puriss., 1.21 ml, 11 mmole) and BF₃.O(C₂ H₅)₂ (30 ml, 1mmole). The orange solution was cooled to -78° and a solution ofacrolein diacetylacetal (Fluka purum 98%, 1.66 ml, 11 mmole) in CH₂ Cl₂(5 ml) was added dropwise. The reaction mixture was allowed to return to0° and stirred during 15 min at this temperature. It was poured on amixture of ice, aq. 10% HCl and ether, and the organic phase was washedwith brine (2 times), sat. NaHCO₃ and brine. It was dried over Na₂ SO₄,concentrated (2.52 g) and bulb-to-bulb distilled (90°/2 Pa) to providethe desired acetate as a yellow oil (1.64 g, purity 95%, Z/E˜1:10, yield63%).

IR(neat): 3070, 3015, 2960, 2900, 2860, 1750, 1665, 1365, 1270, 1220,1185, 1100, 945, 900, 820 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): isomer E 7.20-7.05(m, 4H); 5.57(dt, J₁ =12, J₂=7, 1H); 3.31(d, J=7, 2H); 2.27(s, 3H); 2.11(s, 3H); 1.30(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): isomer Z 168.1(s); 149.1(s); 137.2(s);136.4(d); 133.0(s); 130.0(d); 125.8(d); 123.4(d); 113.4(d); 34.4(s);31.6(t); 31.4(3q); 20.6(q); 18.7(q) δ ppm.

MS: 246(M⁺, 14), 231(7), 204(8), 189(68), 171(12), 147(27), 129(10),115(11), 105(8), 91(11), 77(5), 57(28), 43(100).

Odor: green, vegetable, floral.

EXAMPLE 2

Preparation of 2-(5-tert-butyl-2-methylbenzyl)propanal

To a stirred solution of3-(5-tert-butyl-2-methyl-1-phenyl)-2-methyl-1-propenyl acetate (26 g, 94mmole, purity 94%) in methanol (60 ml) was added K₂ CO₃ (1.38 g, 10mmole). There was a slow exothermy and the temp. of the mixture wasmaintained below 35° with a water bath. After 1 h at 25°, GC analysisindicated complete disappearance of the starting acetate. The mixturewas then diluted with ether, washed with sat. NaHCO₃ and brine, driedover Na₂ SO₄ and concentrated to a yellow oil (20.8 g). Distillation ona 15 cm Vigreux column under reduced pressure gave the desired2-(5-tert-butyl-2-methylbenzyl)propanal (18.8 g, purity 89%, yield 92%).

IR(neat): 2970, 2910, 2890, 2810, 2710, 1725, 1500, 1460, 1365, 1275,1145, 825 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.73(d, J=2, 1H); 7.16(dd, J₁ =8, J₂ =2, 1H);7.12(d, J=2, 1H); 7.08(d, J=8, 1H); 3.10(dd, J₁ =14, J₂ =6, 1H); 2.65(m,1H); 2.56(dd, J₁ =14, J₂ =8, 1H); 2.28(s, 3H); 1.30(s, 9H); 1.12(d, J=7,3H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 204.5(d); 148.9(s); 136.6(s); 133.0(s);130.2(d); 126.8(d); 123.4(d); 47.0(d); 34.3(s,t); 31.4(3q); 18.9(q);13.5(q) δ ppm.

MS: 218(M⁺, 15), 203(72), 185(13), 161(41), 145(100), 131(22), 115(22),105(26), 91(25), 77(13), 57(28), 41(27).

Odor: described above.

The starting 3-(5-tert-butyl-2-methyl-1-phenyl)-2-methyl-1-propenylacetate was prepared as follows.

To 4tert-butyl-toluene (88.8 g, 0.6 mole) at 0° there was added TiCl₄(Fluka puriss., 38.0 g, 21.9 ml, 200 mmole) and BF₃.O(C₂ H₅)₂ (0.5 ml,0.56 g, 4 mmole). The stirred mixture was cooled to -15° (dryice-acetone bath) and a solution of methacrolein diacetylacetal (Flukapurum, 34.4 g, 200 mmole) in 4tert-butyl-toluene (30 ml) was addeddropwise during 0.5 h, while maintaining the temperature between -10°and -20°. The reaction mixture was then stirred during 30 min between-10° and +10° and diluted with ether. It was washed with aq. 10% HCl,brine (2 times), sat. aq. NaHCO₃ and brine. It was dried over Na₂ SO₄,and concentrated under reduced pressure (142 g). Vacuum distillation ona 15 cm Vigreux column gave a first fraction containing 98% of4-tert-butyl-toluene (98.6 g). The second fraction (bath temp.180-210°/0.6×10² Pa) contained the desired acetate (29.6 g, purity 86%,Z/E˜2:84, yield 49%).

IR(neat): 2955, 2900, 2860, 1745, 1675, 1360, 1225, 1100, 1090 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 7.16(dd, J₁ =8, J₂ =2, 1H); 7.13(d, J=2, 1H);6.88(s, 1H); 3.27(s, 2H); 2.26(s, 3H); 2.13(s, 3H); 1.64(s, 3H); 1.30(s,9H) δ ppm.

NMR(¹³ C, 90 MHz, CDCl₃): 168.3(s); 148.71(s); 136.1(s); 133.6(s);130.0(d); 126.6(d); 123.3(d); 120.7(s); 38.0(t); 34.3(s); 31.4(3q);20.8(q); 18.9(q); 13.9(q) δ ppm.

MS: 260(M⁺, 15), 218(25), 203(72), 185(13), 161(41), 145(15), 133(30),115(14), 105(13), 77(6), 57(32), 43(100), 29(11).

EXAMPLE 3

Preparation of 4tert-butyl-2-(3,3-dimethoxypropyl)-1-methylbenzene

To a solution of 3-(5-tert-butyl-2-methyl-1-phenyl)propanal (1.06 g, 5mmole) in methanol (10 ml), at room temperature, there was added conc.HCl (3 drops). After 3 h, the solution was poured into a mixture ofether and sat. NaHCO₃ for extraction. The organic phase was washed withNaHCO₃, dried over K₂ CO₃ and concentrated (1.25 g). After bulb-to-bulbdistillation (120°/6 Pa), the desired product was obtained with 95%purity (1.2 g, yield 91%) and presenting the following analyticalcharacters:

IR(neat) : 2980, 2920, 2890, 2840, 1510, 1465, 1390, 1370, 1280, 1200,1140, 1090, 1065, 920, 830 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 7.17(d, J=2, 1H); 7.14(dd, J₁ =8, J₂ =2, 1H);7.08(d, J=8, 1H); 4.42(t, J=6, 1H); 3.35(s, 6H); 2.66(m, 2H); 2.28(s,3H); 1.89(m, 2H); 1.30(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 148.9(s); 139.3(s); 132.9(s); 130.0(d);125.9(d); 122.9(d); 104.2(d); 52.8(2q); 34.3(s); 33.1(t); 31.5(q);28.6(t); 18.7(q) δ ppm.

MS: 250(M⁺,<1), 235(1), 218(14), 203(20), 186(22), 171(56), 161(43),145(24), 131(43), 106(18), 91(15), 75(100), 57(22), 41(15).

Odor: floral, pleasant.

EXAMPLE 4

Preparation of 5-tert-butyl-2-indancarbaldehyde

To a suspension of pyridinium chlorochromate (FCC, Fluka, 3.24 g, 15mmole) in dichloromethane (20 ml), there was added at room temperature,a solution of 5-tert-butyl-2-indanmethanol (2.04 g, 10 mmole) indichloromethane (10 ml). The mixture was stirred for 5 h at roomtemperature. It was diluted in ether (50 ml), filtered on CELITE®, thenon a FLORISIL® column (Fluka), and concentrated. Bulb-to-bulbdistillation provided 5-tert-butyl-2-indancarbaldehyde (1.47 g,purity>99%, yield 72%) as a colorless oil.

NMR(¹ H, 360 MHz, CDCl₃): 9.77(d, J=2, 1H); 7.27(s, 1H); 7.22(d, J=8,1H); 7.16(d, J=8, 1H); 3.35-3.10(m, 5H); 1.31(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 203.0(d); 150.1(s); 141.0(s); 138.1(s);124.1(d); 124.0(d); 121.5(d); 50.9(d); 34.6(s); 33.1 (t); 32.5(t);31.5(q) δ ppm.

MS: 202(M⁺,36), 187(100), 169(10), 157(10), 141(11), 129(18), 115(19),91(6), 77(3), 57(6), 41(6).

Odor: described above.

The starting alcohol was prepared according to Scheme III, as follows.

5-tert-butyl-1-indanone

To a solution of tert-butylbenzene (88.9 g, 0.7 mole) and of3-chloropropionyl chloride (Fluka, 93.8 g, 0.7 mole) in CH₂ Cl₂ (105ml), at 0°, there was added portionwise AlCl₃ (95.7 g, 0.7 mole) over 2h. After 3 h at 0°, the mixture was poured on ice and diluted with CH₂Cl₂ (200 ml). The organic phase was washed with water (2 times) andconcentrated. The residue was dissolved in ether, washed with aq. sat.NaHCO₃ and brine, dried over Na₂ SO₄ and concentrated (152 g).Crystallizing in petroleum ether 30-50°, at -30°, provided colorlesscrystals (117 g, purity>99%, yield 52%) of1-(4-tert-butyl-1-phenyl)-3-chloro-1-propanone.

M.p. 35-37°.

NMR(¹ H, 360 MHz, CDCl₃): 7.90(d, J=8, 2H); 7.49(d, J=8, 2H); 3.92(t,J=7, 2H); 3.43(t, J=7, 2H; 1.34(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 196.2(s); 157.3(s); 133.7(s); 128.0(2d);125.7(2d); 41.1(t); 38.8(t); 35.1(s); 31.0(3q) δ ppm.

MS: 224(M⁺,4), 209(13), 173(9), 161(100), 146(7), 118(9), 91(11), 77(4),63(5), 41(2).

This propanone (116 g, 0.51 mole) was dissolved in conc. H₂ SO₄ (920 ml)and heated to 100° under stirring (release of HCl). After 1.5 h, themixture was cooled and poured on a mixture of ice (3.0 kg), NaCl (230 g)and ether (400 ml), the organic phase was washed with H₂₀ O, aq. sat.NaHCO₃ and brine, dried over Na₂ SO₄ and evaporated (97 g).Crystallizing from petroleum ether 30-50°, at -30°, provided colorlesscrystals (74 g, purity>99%) of 5-tert-butyl-1-indanone.

M. p 39-40°.

IR(CHCl₃): 2960, 2880, 1708, 1603, 1325, 1085, 710 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 7.69(d, J=8, 1H); 7.48(s, 1H); 7.43(d, J=8,1H); 3.12(t, J=6, 2H); 2.67(m, 2H); 1.36(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 206.5(s); 158.8(s); 155.5(s); 134.8(s);125.0(d); 123.3(d); 123.2(d); 36.5(t); 35.4(s); 31.2(q); 25.9(t) δ ppm.

MS: 188(M⁺,31), 173(100), 145(23), 131(29), 115(12), 103(3), 91(8),77(5), 51(3),41(3).

Odor: vaguely cresolic.

b) ethyl 5-tert-butyl-2-indancarboxylate

A dispersion of NaH (80% in oil, 4.32 g, 144 mmole NaH) was washed withpentane, and toluene (140 ml) and diethyl carbonate (34 g, 288 mmole)were added thereto. The mixture was heated to 60° and there was addedover 2 h a solution in toluene (20 ml) of the indanone prepared in a)(7.52 g, 40 ml). The reaction mixture was kept under stirring at 60° for6 h.

It was poured on an excess of H₂ O/CH₃ COOH 1:1 and extracted withpetroleum ether 30-50°, washed with aq. sat. NaHCO₃ and brine, driedover Na₂ SO₄ and concentrated (10.8 g). After bulb-to-bulb distillation(150°/10 Pa), there were obtained 7.12 g of ethyl5-tert-butyl-1-oxo-2-indancarboxylate.

IR(neat): 2960, 2860, 1730-1700, 1598, 1360, 1320, 1250, 1205, 1150,1080, 1010 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 77.0(d, J=8, 1H); 7.50(s, 1H); 7.45(d, J=8,1H); 4.25(q, J=7, 2H); 3.71(dd, J₁ =8, J₂ =4, 1H); 3.54(dd, J₁ =17, J₂=4, 1H); 3.35(dd, J₁ =17, J₂ =8, 1H); 1.36(s, 9H); 1.32(t, J=7, 3H) δppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 199.2(s); 169.4(s); 159.8(s); 154.0(s);132.9(s); 125.6(d); 124.3(d); 123.0(d); 61.6(t); 53.6(d); 35.5(s);31.1(3q); 30.4(t); 14.2(q) δ ppm.

MS: 260(M⁺,61), 245(25), 215(24), 199(60), 186(77), 171(100), 157(16),143(11), 131(34),115(31),91(18), 57(76), 41(31).

A solution of this compound (4.68 g, 16.2 mmole) in ethyl acetate (50ml) was stirred at room temperature, in the presence of 5% Pd/C (0.48 g)under H₂ (1 atm) during 12 h. The catalyst was filtered on CELITE® andthe solution concentrated (4.25 g). Chromatography on SiO₂ (106 g) withpentane/ether 9:1 as eluting agent and bulb-to-bulb distillation (160°/5Pa) provided the desired ethyl 5-tert-butyl-2-indancarboxylate (3.47 g,purity>99%, yield 86%).

NMR(¹ H, 360 MHz, CDCl₃): 7.24(s, 1H); 7.20(d, J=8, 1H); 7.13(d, J=8,1H); 4.18(q, J=7, 2H); 3.40-3.10(m, 5H); 1.31(s, 9H); 1.28(t, J=7, 3H) δppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 175.4(s); 149.8(s); 141.5(s); 138.7(s);123.8(d); 123.7(d); 121.2(d); 60.6(t); 43.8(t); 36.3(t); 35.8(t);34.5(s); 31.6(3q); 14.3(q) δ ppm.

MS: 246(M⁺,25), 231(100), 201(3), 172(25), 157(60), 129(20), 115(20),91(4), 79(4), 57(20), 41(7).

Odor: floral, lily of the valley, hydroxycitronellal.

c) 5-tert-butyl-2-indanmethanol

To a suspension of LiAlH₄ (0.27 g, 7.2 mmole) in ether (10 ml), at roomtemperature, there was added a solution of the carboxylate obtainedaccording to b) (2.2 g, 8.9 mole) in ether (10 ml). Reaction was allowedunder stirring for 2 h, at room temperature. The mixture was diluted inether, poured on H₂ O and the organic phase was washed with 10% aq. HCl,H₂ O, sat. NaHCO₂ and brine. It was dried over Na₂ SO₄, concentrated andbulb-to-bulb distilled (200°/40 Pa) to give the above-mentioned alcoholas a colorless oil (1.86 g, purity>99%, yield 100%).

NMR(¹ H, 360 MHz, CDCl₃): 7.24(s, 1H); 7.18(d, J=8, 1H); 7.13(d, J=8,1H); 3.66(d, J=6, 2H); 3.04(m, 2H); 2.71(m, 3H); 1.62(broad s, 0H)1.31(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 149.5(s); 142.5(s); 139.7(s); 124.1(d);123.4(d); 121.5(d); 66.7(t); 41.7(d); 39.9(t); 35.3(t); 34.5(s);31.6(3q) δ ppm.

MS: 204(M⁺,21), 189(100), 171(15), 143(14), 129(16), 115(13), 91(6),77(3), 57(7),41(5).

EXAMPLE 5

Preparation of 5-tert-butyl-2-methyl-2-indancarbaldehyde

To a solution of potassium tert-butoxide (Fluka, 0.45 g, 4 mmole) and of5-tert-butyl-2-indancarbaldehyde (ex. 4; 0.71 g, 3.5 mmole), there wasadded at room temperature and under N₂, methyl iodide (0.56 g, 4 mmole)and reaction was allowed at room temperature, under stirring. Themixture was taken in ether and washed with NH₄ Cl and brine, dried overNa₂ SO₄ and concentrated (0,9 g). Chromatography on SiO₂ (30 g), withtoluene as eluting agent, provided 50 mg (purity>99%, yield 7%) of thedesired aldehyde.

NMR(¹ H, 360 MHz, CDCl₃): 9.65(s, 1H); 7.23(s, 1H); 7.22(d, J=8, 1H);7.13(d, J=8, 1H); 3.36(d, J=16, 1H); 3.33(d, J=16, 1H); 2.76(d, J=16,1H); 2.74(d, J=16, 1H); 1.31(s, 9H); 1.30(s, 3H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 204.1(d); 150.1(s); 140.8(s); 137.9(s);124.2(d); 124.0(d); 121.6(d); 54.3(s); 41.1(t); 40.6(t); 34.6(s);31.5(3q); 21.1(q) δ ppm.

MS: 216(M⁺,37), 201(100), 183(4), 171(5), 157(16), 141(9), 129(18),115(5), 91(7), 71(6), 57(24),41(8).

Odor: described above.

EXAMPLE 6

Preparation of 2-(5-tert-butyl-2-indanyl)-1,3-dioxolane

A mixture of 5-tert-butyl-2-indancarbaldehyde (ex. 4; 9.8 mmole),ethyleneglycol (6.1 g, 98 mmole) and p-toluenesulfonic acid (95 mg, 0.5mmole) in cyclohexane (25 ml), was heated to reflux (80°) during 3 hwith a Dean-Stark type trap. The cooled mixture was poured on ether andaq. sat. NaHCO₃, and the organic phase was washed with aq. sat. NaHCO₃,dried over K₂ CO₃ and concentrated. After bulb-to-bulb distillation, thedesired dioxolane was obtained.

IR: 2980, 2890, 1500, 1400, 1370, 1275, 1210, 1155, 1130, 1080, 1050,980, 950, 925, 830 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 7.24(s, 1H); 7.18(d, J=8, 1H); 7.13(d, J=8,1H); 4.87(d, J=6, 1H); 4.0(m, 2H); 3.88(m, 2H); 3.10-2.85(m, 4H);2.71(m, 1H); 1.31(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 149.5(s); 142.4(s); 139.6(s); 124.0(d);123.4(d); 121.4(d); 106.9(d); 65.1(t); 43.0(d); 34.5(tz); 33.9(t);31.6(3q) δ ppm.

MS: 246(M⁺,16), 231(6), 184(30), 169(15), 157(9), 141(8), 128(13),115(13), 73(100), 57(16), 45(27), 41(8), 29(9).

Odor: floral.

EXAMPLE 7

Preparation of 5-tert-butyl-1-indanacetaldehyde

Prepared in an analogous manner to that described in Example 4, viaoxidation of 2-(5-tert-butyl-1-indanyl)-1-ethanol (3.85 g, 17.6 mmole)in CH₂ Cl₂ (40 ml), by means of PCC (5.73 g, 25 mmole) in CH₂ Cl₂ (60ml). After the treatment described and bulb-to-bulb distillation(150°/40 Pa), there was obtained the desired carbaldehyde (2.34 g, yield62%).

IR(neat): 2960, 2900, 2860, 2710, 1725, 1490, 1360, 1260, 830 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.88(t, J=2, 1H); 7.28(s, 1H); 7.22(d, J=8,1H); 7.08(d, J=8, 1H); 3.62(m, 1H); 2.95-2.85(m, 2H); 2.62(ddd, J₁ =17,J₂ =9, J₃ =2, 1H); 2.43(m, 1H); 1.70(m, 1H); 1.32(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 202.2(d); 150.1(s); 143.6(s); 142.5(s);123.5(d); 122.9(d); 121.5(d); 49.5(d); 38.6(d); 34.6(s); 32.7(t);31.6(3q); 31.5(t) δ ppm.

MS: 216(M⁺,44), 201(111), 173(79), 157(98), 143(37), 129(72), 115(73),102(5), 91(23), 77(10), 57(33),41(8), 29(8).

Odor: metallic, floral.

The starting 2-(5-tert-butyl-1-indanyl)-1-ethanol was prepared from5-tert-butyl-1-indanone[ex. 4 a)], as follows.

a) methyl 5-tert-butyl-1-indanacetate

To a suspension of sodium hydride (3.6 g of a 50% dispersion in oil, 75mmole) previously washed with petroleum ether 30-50, in 100 ml oftetrahydrofuran (THF), there were added dropwise at 10-20° 13.8 g (75mmole) of trimethylphosphonoacetate in 100 ml of THF. 15 min after theend of the addition, there was added to the reaction mixture, at 11-15°,a solution of the above-cited indanone (10.2 g, 55 mmole) in THF (150ml). The mixture was kept under stirring for 16 h at 25°, then it waspoured on 500 ml of water and extracted with ether. The combined organicextracts were washed with brine (2 times), dried (Na₂ SO₄) andconcentrated until forming an oil which became solid (12.6 g; isomermixture). This product was crystallized in ether at -30°, to provide5.56 g of methyl (E)-(5-tert-butyl-1-indanylidene)acetate.

M. p. 116.5-117.5°.

IR(CHCl₃): 2960, 1690, 1630, 1605, 1435, 1355, 1315, 1290, 1175, 1090,830 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 7.53(d, J=8, 1H); 7.37(s, 1H); 7.30(d, J=8,1H); 6.27(t, J=2.5, 1H); 3.76(s, 3H); 3.29(m, 2H); 3.06(t, J=6, 2H);1.33(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 168.1(s); 163.4(s); 154.8(s); 149.7(s);137.4(s); 124.4(d); 122.2(d); 121.3(d); 106.4(d); 50.9(q); 35.0(s);31.5(t); 31.3(3q); 30.7(t) δ ppm.

MS: 244(M⁺,43), 229(100), 213(15), 197(14), 188(9), 169(15), 155(27),141(25), 128(34),115(23), 85(10), 57(13), 41(7).

A solution of this compound (7.4 g, purity 94%, 30 mmole) in ethylacetate (150 ml) was hydrogenated in the presence of 5% Pd/C (0.68 g,0.3 mmole) for 1 h. After filtration of the catalyst on CELITE® andconcentration of the solution (7.93 g), bulb-to-bulb distillation(110°/35 Pa) provided methyl 5-tert-butyl-1-indanacetate (7.1 g,purity>99%, yield 93%).

IR(neat): 2970, 1735, 1435, 1360, 1270, 1190, 1170, 830 cm₋₁.

NMR(¹ H, 360 MHz, CDCl₃): 7.26(s, 1H); 7.20(d, J=8, 1H); 7.00(d, J=8,1H); 3.72(s, 3H); 3.55(m, 1H); 3.0-2.7(m, 3H); 2.5-2.3(m, 2H); 1.73(m,1H); 1.32(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 173.3(s); 149.9(s); 143.7(s); 142.7(s);123.4(d); 122.9(d); 121.5(d); 51.5(q); 41.0(d); 39.7(t); 34.5(s);32.7(t); 31.6(3q); 31.3(t) δ ppm.

MS: 246(M⁺,28), 231(58), 189(52), 173(74),157(65), 143(32),129(100),115(54), 91(15), 77(7), 57(31), 41(7).

b) 2-(5-tert-butyl-1-indanyl)-1-ethanol

Prepared from the ester described under a) (6.3 g, 25 mmole), in ananalogous manner to that described in ex. 4 c), by means of LiAlH₄ (38mmole). There were added 2 ml of ethyl acetate to the reaction mixture,then 4.85 ml of aq. 1N NaOH and the mixture was stirred for 30 min atroom temperature. After addition of Na₂ SO₄ and filtration, it waswashed with ether and evaporated (5.5 g). Bulb-to-bulb distillation(115°/30 Pa) provided the desired alcohol (5.5 g, purity>99%, yield99%).

IR(neat): 3320, 2960, 2860, 1490, 1360, 1265, 1060, 1025, 825 cm⁻.

NMR(¹ H, 360 MHz, CDCl₃): 7.27(s, 1H); 7.21(d, J=8, 1H); 7.14(d, J=8,1H); 3.81(m, 2H); 3.2(m, 1H); 3.0-2.8(m, 2H); 2.32(m, 1H); 21.5(m, 1H);1.70(m, 2H); 1.32(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 149.6(s); 144.0(s); 143.7(s); 123.2(d);123.0(d); 121.4(d); 61.7(t); 41.1(d); 38.0(t); 34.5(s); 32.5(t);31.6(3q) δ ppm.

MS: 218(M⁺,56), 203(99), 200(3), 185(25), 173(100), 161(34), 143(30),128(22), 115(20), 91(8), 77(4), 57(25), 41(6), 31(9).

EXAMPLE 8

Preparation of 3-(3-tert-butyl-5-methylphenyl)propanal

To 1.2 g (5.7 mmole) of (E)-3-(3-tert-butyl-5-methylphenyl)-2-propenalin ethanol (20 ml) there were added 5% Pd/C (0.12 g) and sodium acetate(0.12 g, 1.4 mmole). The mixture was hydrogenated at room temperatureand atmospheric pressure during 6 h. After filtration of the catalyst,the solvent was evaporated (1.2 g). The raw product was dissolved in CH₂Cl₂ (20 ml) and a suspension of PCC (0.62 g, 2.8 ml) in CH₂ Cl₂ (20 ml)was added thereto at room temperature. After 2 h, the mixture wasdiluted in ether (100 ml) filtered on a FLORISIL® column (Fluka) andconcentrated (1.2 g). Bulb-to-bulb distillation (80°/10 Pa) provided3-(3-tert-butyl-5-methylphenyl)propanal (6.88 g, purity>95%, yield 70%).

IR(neat): 2960, 2860, 1720, 1595, 1470, 1360, 1220, 860, 710 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.82(t, J=1.5, 1H); 7.06(s, 1H); 7.02(s, 1H);6.83(s, 1H); 2.92(t, J=8, 2H); 2.76(dt, J₁ =1.5, J₂ =8, 2H); 2.32(s,3H); 1.30(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 201.8(d); 151.5(s); 139.9(s); 137.5(s);126.2(d); 124.2(d); 122.4(d); 45.5(t); 34.5(s); 31.4(3q); 28.3(t);21.6(q) δ ppm.

MS: 204(M⁺,33), 189(42), 161(49), 145(100), 133(25), 119(23), 105(20 ),91(18), 77(9), 65(4), 57(18), 41(6), 29(5).

Odor: described above.

The starting unsaturated aldehyde was prepared according to Scheme II,as follows. 5-Tert-butyl-1,3-dimethylbenzene (Fluka, 190 g, 1.17 mole)was electrochemically oxidized (anode: graphite; cathode: inox; currentdensity: 30 mA/cm² ; 4 F/mole) at a temperature of about 35° in solutionin methanol, using sodium p-toluenesulfonate as electrolyte. Afterdistillation (Vigreux), there were obtained 77.3 g of1-tert-butyl-3-(dimethoxy-methyl)-5-methylbenzene, having a purity of87% (yield 26%).

B.p. 118-128°/11×10² Pa.

IR(neat): 2980, 2920, 2840, 1745, 1605, 1455, 1370, 1235, 1200, 1175,1120, 1090, 1070, 1000, 920, 870, 715 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 7.25(s, 1H); 7.17(s, 1H); 7.08(s, 1H); 5.35(s,1H); 3.34(s, 6H); 2.35(s, 3H); 1.32(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 151.2(s); 137.7(s); 137.4(s); 126.3(d);124.5(d); 120.7(d); 103.9(d); 52.9(2q); 34.6(s); 31.4(3q); 21.6(q) δppm.

MS: 222(M+,2), 207(3), 191(100), 177(5), 161(9), 133(9), 115(6), 105(8),91(8), 75(10), 57(3), 41(2).

To the thus obtained acetal (12.7 g, 50 mmole) there was added, at -10°,quickly and under stirring, a solution of ZnCl₂ (0.27 g, 2 mmole) inethyl acetate (2.7 ml). After 5 min, 85% H₃ PO₄ was added (0.24 ml, 3.5mmole). After 15 min, ethylvinylether was added dropwise (Fluka purum,7.3 ml, 75 mmole) while maintaining the temperature between -10 and 0°.After 2.5 h at 0° and 15 h at room temperature, chromatographic analysisindicated the formation of 65% of the intermediate acetals. This rawmixture of acetals was added by means of a cannula to a mixture offormic acid (12.5 ml), sodium formate (4 g) and water (6.5 ml), and thewhole was heated to 110° with a bath, while continuously distilling thevolatiles (b. p. 80-90°/10⁶ Pa), for 1 h. The residue was diluted inwater (40 ml) and petroleum ether 30-50° (40 ml) for extraction. Theorganic phase was washed, dried and concentrated. The raw product (12.1g, purity 66%, yield 79%) was distilled on a Vigreux column (5 cm) toprovide (E)-3-(3-tert-butyl-5-methylphenyl)-2-propenal (6.4 g).

B. p. 70-82°/10 Pa.

IR(neat): 2960, 2860, 1670, 1620, 1590, 1475, 1360, 1240, 1125, 970, 700cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.69(d, J=8, 1H); 7.46(d, J=15, 1H); 7.38(s,1H); 7.29(s, 1H); 7.22(s, 1H); 6.72(dd, J₁ =16, J₂ =8, 1H); 2.38(s, 3H);1.33(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 193.8(d); 157.7(d); 152.1(s); 138.4(s);133.7(s); 129.5(d); 128.2(d); 126.2(d); 123.1(d); 34.6(s); 31.2(3q);21.5(q) δ ppm.

MS: 202(M⁺,12), 187(25), 159(13),145(100), 128(12), 115(16), 105(4),91(8), 79(4), 65(3), 55(3),41(3).

EXAMPLE 9

Preparation of 3-(3-tert-butyl-5-methylphenyl)-2-methylpropanal

Prepared by hydrogenation of3-(3-tert-butyl-5-methylphenyl)-2-methyl-2-propenal (2,32 g, 8,5 mmole),in a similar manner to that described in Example 8 (reaction 2.5 h).After the treatment described and bulb-to-bulb distillation (90-105°/10Pa), there were obtained 1.5 g of product having a purity of 86% (yield78%). Purification on a SiO₂ column, with CH₂ Cl₂ as eluting agent,provided the desired propanal 94% pure.

IR(neat): 2970, 2870, 1725, 1600, 1475, 1450, 1360, 1225, 860, 715 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.72(d, J=2, 1H); 7.05(s, 1H); 6.98(s, 1H);6.80(s, 1H); 3.04(dd, J₁ =13, J₂ =6, 1H); 2.64(m, 1H); 2.56(dd, J₁ =13,J₂ =8, 1H); 2.32(s, 3H); 1.30(s, 9H); 1.08(d, J=7, 3H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 204.6(d); 151.4(s); 138.4(s); 137.6(s);126.9(d); 124.2(d); 123.2(d); 48.1(d); 36.9(t); 34.5(s); 31.4(3q);21.6(q); 13.3(q) δ ppm.

MS: 218(M⁺,32), 203(20), 190(11), 175(100), 161(35), 145(80), 133(57),115(28), 105(45), 91(28), 77(14),57(32), 41(22), 29(21).

Odor: described above.

The starting unsaturated aldehyde was prepared from1-tert-butyl-3-(dimethoxymethyl)-5-methylbenzene (see ex. 8), accordingto scheme II, as follows. To a solution of the above-mentioned acetal(22.2 g, 90 mmole) in THF (50 ml), there was added 10% aq. HCl (10 ml)and the mixture was stirred during 1.5 h. After the usual treatment anddistillation under vacuum (10³ Pa), 2 fractions were obtained, of whichthe purest (11.2 g) contained 3-tert-butyl-5-methylbenzenaldehyde 95%pure.

B.p. 112-114°/10³ Pa

IR(neat): 2980, 2880, 1700, 1600, 1480, 1370, 1305, 1235, 1170, 1160,875, 710 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.98(s, 1H); 7.71(s, 1H); 7.50(s, 1H); 7.47(s,1H); 2.43(s, 3H); 1.35(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 192.9(d); 152.2(s); 138.5(s); 136.5(s);132.6(d); 127.8(d); 123.9(d); 34.7(s); 31.2(3q); 21.4(q) δ ppm.

MS: 176(M⁺,26), 161(100), 145(2), 133(31), 115(16), 105(32), 91(18),77(9), 65(7), 51(5), 41(11), 29(7).

To a solution of this benzaldehyde (3.55 g, 18 mmole) in methanol (20ml), there was added K₂ CO₃ (2.76 g, 20 mmole) and the mixture washeated to reflux (65°). A solution of propanal (1.71 g, 24 mmole) inmethanol (5 ml) was added dropwise, during 1 h. After having heated toreflux for yet 1 h, the mixture was cooled and diluted in ether, washedwith aq. sat. NaHCO₃ and brine, dried over Na₂ SO₄ and concentrated(3.75 g). After bulb-to-bulb distillation (125°/10 Pa), there wasobtained 3-(3-tert-butyl-5-methylphenyl)-2-methyl-2-propenal as acolorless oil (1.83 g, purity 79%, yield 57%).

IR(neat): 2970, 2930, 2870, 1675, 1622, 1595, 1480, 1445, 1400, 1365,1280, 1230, 1195, 1030, 920, 835, 705 c⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.58(s, 1H); 7.35(s, 1H); 7.25(s, 1H); 7.18(s,1H); 2.40(s, 3H); 2.09(s, 3H); 1.35(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 195.7(d); 151.6(s); 150.8(d); 138.0(2s);134.9(s); 127.8(d); 127.7(d); 124.5(d); 34.6(s); 31.3(3q); 21.7(q);11.0(q) δ ppm.

MS: 216(M⁺,8), 201(20), 173(18), 159(100), 145(8), 131(19), 128(11),115(12), 105(7), 91(7), 77(4), 57(3), 41(3), 29(2).

EXAMPLE 10

Preparation of 3-(3,3-dimethyl-5-indanyl)propanal and3-(1,1-dimethyl-5-indanyl)propanal

Prepared by hydrolysis of (E)-3-(3,3-dimethyl-5-indanyl)-1-propenylacetate [1.93 g, 7.4 mmole; mixture containing 58% of this compound and25% of its (1,1-dimethyl-5-indanyl) isomer] by means of H₂ SO₄ (24 ml)in an analogous manner to that described in Example 1. Afterbulb-to-bulb distillation (100°/11 Pa), there was obtained a colorlessoil (1.43 g, yield 90%, purity 95%) containing 58% of3-(3,3-dimethyl-5-indanyl)propanal and 28% of3-(1,1-dimethyl-5-indanyl)propanal.

IR(neat): 2960, 2860, 2720, 1728, 1490, 1450, 1360, 825 cm⁻¹.

3-(3,3-Dimethyl-5-indanyl)propanal presented the following analyticalcharacters:

NMR(¹ H, 360 MHz, CDCl₃): 9.82(t, J=15, 1H); 7.10(d, J=8, 1H); 6.96(d,J=8, 1H); 6.95(s, 1H); 2.94(t, J=7, 2H); 2.84(t, J=7, 2H); 2.75(t, J=7,2H); 1.91(t, J=7, 2H); 1.24(s, 6H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 201.8(d); 153.1(s); 140.8(s); 138.4(s);126.2(d); 124.5(d); 121.9(d); 45.6(t); 43.9(s); 41.6(t); 29.6(t);28.6(2q); 28.2(t) δ ppm.

MS: 202(M⁺,22), 187(100), 159(4), 143(74), 128(40), 115(21), 91(9),77(6), 63(3), 51(3), 39(4), 29(9).

Odor: described above.

The starting acetate was prepared from 1,1-dimethylindane [5.2 g, 35mmole; this compound is prepared via known methods; see, for example, M.T. Bogert and al., J. Amer. Chem. Soc. 56, 185 (1934); S. T. Bright andal., J. Org. Chem. 55, 1338 (1990) and ref. there-cited] by reactingwith 1,1-dimethylindane acrolein diacetylacetal (7.9 ml, 52 mmole), inthe presence of TiCl₄ (5.8 ml, 52 mmole) and of BF₃.O(C₂ H₅)₂ (0.25 ml,1 mmole), in an analogous manner to that described in Example 1. Afterpurification by chromatography (SiO₂, cyclohexane/ether 9:1) andbulb-to-bulb distillation (120°/10 Pa), there was obtained a colorlessoil (2.94 g, yield 32%, purity 93%) consisting of a mixture of(E)-3-(3,3-dimethyl-5-indanyl)-1-propenyl acetate (58%) and of(E)-3-(1,1-dimethyl-5-indanyl)-1-propenyl acetate (25%).

IR(neat) : 2960, 2860, 1755, 1665, 1370, 1225, 1100, 935, 900 cm⁻¹.

The above-mentioned major isomer presented the following analyticalcharacters:

NMR(¹ H, 360 MHz, CDCl₃): 7.18(dt, J₁ =12, J₂ =1.5, 1H); 7.10(d, J=8,1H); 6.96(d, J=8, 1H); 6.95(s, 1H); 5.58(dt, J₁ =12, J₂ =7, 1H); 3.32(d,J=7, 2H); 2.84(t, J=7, 2H); 2.11(s, 3H); 1.91(t, J=7, 2H); 1.25(s, 6H) δppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 168.1(s); 153.0(s); 140.8(s); 137.8(s);136.1(d); 126.3(d); 124.4(d); 121.9(d); 114.2(d); 43.9(s); 41.6(t);33.6(t); 29.6(t); 28.6(2q); 20.7(q) δ ppm.

MS: 244(M⁺,32), 229(25), 202(21), 187(100), 169(8), 157(7), 146(19),131(30), 115(30), 91(14), 77(5), 57(9), 43(64).

EXAMPLE 11

Preparation of 3-(1,1-dimethyl-5-indanyl)-2-methylpropanal and3-(3,3-dimethyl-5-indanyl)-2-methylpropanal

Prepared by hydrolysis of(E)-3-(1,1-dimethyl-5-indanyl)-2-methyl-1-propenyl acetate [2 g, 7mmole; mixture 51% of this compound and 33% of its3,3-dimethyl-5-indanyl isomer] in methanol (20 ml), by means of K₂ CO₃(0.1 g, 0.7 mmole). After bulb-to-bulb distillation (100°/10 Pa), therewas obtained a colorless oil (1.33 g, yield 84%, purity 95%) containing59% of 3-(1,1-dimethyl-5-indanyl)-2-methylpropanal and 31% of3-(3,3-dimethyl-5-indanyl)-2-methylpropanal.

IR(neat): 2960, 2860, 2710, 1725, 1490, 1455, 1360, 1125, 835 cm⁻¹.

3-(1,1-Dimethyl-5-indanyl)-2-methylpropanal presented the followinganalytical characters:

NMR(¹ H, 360 MHz, CDCl₃): 9.72(d, J=1.5, 1H); 7.04(d, J=7.5, 1H);6.99(s, 1H); 6.96(d, J=7.5, 1H); 3.04(dd, J₁ =13, J₂ =6, 1H); 2.84(t,J=7, 2H); 2.63(M, 1H); 2.57(dd, J₁ =13, J₂ =8, 1H); 1.91(t, J=7, 2H);1.24(s, 6H); 1.09(d, J=7, 3H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 204.7(d); 150.8(s); 143.2(s); 136.7(s);127.1(d); 125.1(d); 121.9(d); 48.2(d); 43.6(s); 41.5(t); 36.6(t);30.0(t); 28.6(2q); 13.3(q) δ ppm.

MS: 216(M⁺,18), 201(100), 173(3), 159(15), 143(54), 128(33), 115(17),91(8), 77(5), 51(3), 39(4), 29(9).

Odor: described above.

The starting acetate was prepared in an analogous manner to thatdescribed in the preceding example, starting from 1,1-dimethylindane(4.75 g, 32 mmole, purity 98%), by means of TiCl₄ (3.5 ml, 32 mmole),BF₃.O(C₂ H₅)₂ (0.25 ml, 1 mmole) and of methacrolein diacetylacetal (5.4ml, 32 mmole). Bulb-to-bulb distillation provided a colorless oil (6 g,purity 65%) containing 40% of(E)-3-(1,1-dimethyl-5-indanyl)-2-methyl-1-propenyl acetate and 22% of(E)-3-(3,3-dimethyl-5-indanyl)-2-methyl-1-propenyl acetate.

IR(neat): 2950, 2855, 1750, 1680, 1480, 1435, 1380, 1365, 1225, 1100,920, 810 cm⁻¹.

The major isomer presented the following analytical characters:

NMR(¹ H, 360 MHz, CDCl₃): 7.05(s, 1H); 7.03(d, J=7.5, 1H); 7.00(s, 1H);6.98(d, J=7.5, 1H); 3.22(s, 2H); 2.84(t, J=7, 2H); 2.13(s, 3H); 1.91(t,J=7, 2H); 1.61(s, 3H); 1.23(s, 6H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 168.3(s); 150.7(s); 143.0(s); 136.9(s);131.1(d); 126.9(d); 124.8(d); 121.8(d); 121.6(s); 43.6(s); 41.5(t);40.2(t); 29.9(t); 28.7(2q); 20.8(q); 13.6(q) δ ppm.

MS: 258(M⁺,12), 243(6), 216(27), 201(100), 183(4), 171(3), 159(5),143(10), 131(37),115(11), 91(8), 71(5), 43(21).

EXAMPLE 12

Preparation of 6-tert-butyl-1-indanacetaldehyde

Prepared in an analogous manner to that described in Example 4, byoxidizing 2-(6-tert-butyl-1-indanyl)-1-ethanol (8.53 g, 32.1 mmole,82.3% pure) in dichloromethane (50 ml), by means of PCC (Fluka, 15.0 g,68 mmole) in dichloromethane (100 ml). After the treatment described andbulb-to-bulb distillation (120°/15 Pa), there was obtained theabove-mentioned compound with a purity of 84% (6.01 g, yield 72.7%).Further purification by chromatography provided the desired compound 98%pure, presenting the following analytical characters:

IR(neat): 2980, 2880, 2620, 1730, 1495, 1370, 1270, 1125, 830 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 9.88(s, CHO); 7.22(d, J=8, 1H); 7.19(s, 1H);7.17(d, J=8, 1H); 3.60-3.67(m, 1H); 2.80-2.96(m, 3H); 2.57-2.66(m, 1H);2.37-2.46(m, 1H); 1.65-1.75(m, 1H); 1.29(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 202.0(d); 149.7(s); 145.3(s); 140.8(s);124.2(d); 124.0(d); 120.2(d); 49.6(t); 39.1(d); 34.6(s); 32.7(t);31.6(3q); 30.9(t) δ ppm.

MS: 216(16), 201(42), 172(45), 159(27), 157(100), 141(21), 131(25),129(61), 117(33),115(51), 91(16), 77(6), 57(11).

Odor: described above.

The starting 2-(6-tert-butyl-1-indanyl)-1-ethanol is prepared from3-(4-tert-butyl-1-phenyl)propanal, as follows:

a. 6-tert-butyl-1-indanone

In a 500 ml flask, 20 g of the above-mentioned propanal 92.2% pure (96.9mmole) are dissolved in 100 ml of acetone Fluka puriss, then 55.4 ml of2.1 M Jones reactant are added dropwise (116.3 mmole; 1.2 eq) whilekeeping the reaction temperature <30° with an ice water bath. After 16 hat room temperature, 10 ml of isopropanol are added and the solvent isevaporated. Extract with ether, wash with brine until neutral pH andconcentrate under vacuum. There were obtained 21.1 g of3-(4-tert-butylphenyl)propanoic acid in the form of pale green crystals,with a GC purity of 90% and the following analytical characters:

M.p.: 147.5-148° C.

IR(CHCl₃): 2960 (broad), 2640, 1710, 1410, 1270, 835 cm-1.

NMR(¹ H, 360 MHz, CDCl₃): 11.9-11.6(broad, COOH); 7.32(d, J=8 Hz, 2H);7.14(d, J=8 Hz, 2H); 2.93(t, J=8 Hz, 2H); 2.68(t, J=8 Hz, 2H); 1.3(s,9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 179.6(s); 149.2(s); 137.1(s); 127.9(2d);125.5(2d); 35.6(t); 34.4(s); 31.4(3q); 30.0(t) δ ppm.

MS: 206(13),191(100), 163(5),145(11),131(56), 117(27), 91(19), 77(7),45(7).

In a 500 ml flask there were suspended 21.1 g of the above-mentionedacid (92.1 mmole) in 10.6 ml of thionyl chloride (Fluka purum 99%, 144.7mmole) then the mixture was heated to 60° and stirred at thistemperature until all the acid had dissolved (˜45 min). Evaporate theexcess of thionyl chloride with water pump vacuum, then bulb-to-bulbdistill (150°/30 Pa). There were obtained 12.88 g of the acid chloride.In a 250 ml sulfuration flask there were dissolved 11.88 g of thischloride (˜52.9 mmole) in 100 ml of CH₂ Cl₂ puriss, then the solutionwas cooled with an ice bath and 8.5 g of aluminium chloride (63 mmole)were added in small portions. After 2 h of stirring at 0°, the reactionmixture is poured on a mixture of ice and ether. The product isextracted with ether, washed with brine, then concentrated under vacuum.There were obtained 10.3 g of raw product containing 86% of6-tert-butyl-1-indanone and 6.1% of 6-tert-butyl-3-indanone.Bulb-to-bulb distillation of this raw product (120°/20 Pa) provided 8.97g of 95% pure product, containing 89.3% of 6-tert-butyl-1-indanone.

IR(CHCl₃): 2960, 1700, 1610, 1490, 1290, 840 cm⁻¹.

NMR(¹ H, 360 MHz, CDCl₃): 7.78(d, J=2 Hz, 1H); 7.66(dd, J=8, 2 Hz, 1H);7.49(d, J=8 Hz, 1H); 3.09(t, J=6 Hz, 2H); 2.68(t, J=6 Hz, 2H); 1.33(s,9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 207.4(s); 152.6(s); 150.8(s); 137.0(s);132.5(d); 126.3(d); 120.0(d); 36.7(t); 34.8(s); 31.4(3q); 25.33(t) δppm.

MS: 188(24), 173(100), 145(21), 131(30), 128(9), 115(10), 91(6), 77(4).

Odor: metallic, dusty, motor oil.

b. methyl (E)-(6-tert-butyl-1-indanylidene) acetate

In a 250 ml three-neck flask, dissolve 8.52 g of 6-tert-butyl-1-indanone(45.3 mmole) in 100 ml of pentane. Then add quickly 10.1 ml oftrimethylphosphonoacetate (68 mmole; 1.5 eq), then dropwise 11.7 ml ofsodium methylate (Fluka, 5.4 M in methanol; 63.4 mmole; 1.4 eq) andstirr at room temperature during 24 h. The reaction mixture is poured ona mixture of ether and sat. aq. NaHCO₃ , extracted with ether, washedwith brine, then concentrated under vacuum to provide 10.7 g of amixture containing 18.9% of methyl 5-tert-butyl-3(1H)-indenacetate, 4.2%of methyl (Z)-(6-tert-butyl-1-indanylidene) acetate and 53.2% of methyl(E)-(6-tert-butyl-1-indanylidene) acetate.

This raw product was used in the following step.

IR(neat): 2980, 1740, 1710, 1680, 1450, 1355, 1200, 1170, 860, 835 cm⁻.

Major isomer:

NMR(¹ H, 360 MHz, CDCl₃): 7.61(d, J=2 Hz, 1H); 7.42(dd, J=8, 2 Hz, 1H);7.28(d, J=8 Hz, 1H); 6.33(t, J=2 Hz, 1H); 3.76(s, 3H); 3.28-3.34(m, 2H);3.03(t, J=6 Hz, 2H); 1.34(s, 9H) δ ppm.

MS: 244(47), 229(100), 213(19), 197(41), 188(43), 169(17), 155(30),141(21), 129(38),115(16), 85(15), 57(11).

c. methyl 6-tert-butyl-1-indanacetate

The hydrogenation of 10.7 g (76.3%; 33.4 mmole) of the mixture of estersprecedingly described was carried out in solution in ethyl acetate (100ml) in the presence of 2.25 g of 5% Pd on carbon. The suspension wasstirred during 17 h under hydrogen atmosphere and provided, afterfiltration of the catalyst and concentration, 10.7 g of raw methyl6-tert-butyl-1-indanacetate with a purity of 80.5%.

The raw product was used in the following step.

IR(neat): 2990, 2940, 1740, 1500, 1440, 1370, 1270, 1180, 830 cm¹.

NMR(¹ H, 360 MHz, CDCl₃): 7.14-7.23(m, 3H); 3.72(s, 3H); 3.53-3.62(m,1H); 2.76-2.94(m, 3H); 2.33-2.48(m, 2H); 2.70-2.80(m, 1H); 1.3(s, 9H) δppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 173.31(s); 149.48(s); 145.45(s); 140.88(s);124.08(d); 123.94(d); 120.25(d); 51.53(q); 41.51(d); 39.85(t); 34.60(s);32.62(t); 31.58(q); 30.67(t) δ ppm.

MS: 246(27), 231(59), 189(41), 173(31), 157(100), 129(70), 115(29),91(8), 57(15).

d. 2-(6-tert-butyl-1-indanyl)-1-ethanol

To a suspension of 1.72 g of LiAlH₄ (45.03 mmole) in 100 ml of ether wasadded dropwise a solution of 10.7 g of methyl6-tert-butyl-1-indanacetate (36.9 mmole) dissolved in 50 ml of ether.After refluxing the suspension during 2 h, 8.6 ml of 1 N NaOH werecarefully added and, after 1 h, the suspension was filtered andconcentrated to give 9.05 g of raw 2-(6tert-butyl-1-indanyl)-1-ethanol78.1% pure. Bulb-to-bulb distillation (150°/20 Pa) provided 8.53 g of2-(6-tert-butyl-1-indanyl)-1-ethanol with a GC purity of 82.3%. Yield ofthe last three steps: 71.0%.

IR(neat): 3320, 2960, 2860, 1480, 1355, 1255, 1150, 820 cm-1.

NMR(¹ H, 360 MHz, CDCl₃): 7.24(d, J=1.5 Hz, 1H); 7.21(dd, J=8, 1, 1H);7.15(d, J=8 Hz, 1H); 3.76-3.84(m, 2H); 3.17-3.27(m, 1H); 2.75-2.94(m,2H); 2.26-2.36(m, 1H); 2.12-2.21(m, 1H); 1.64-1.76(m, 2H);1.40-1.44(broad, 0H); 1.32(s, 9H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 149.3(s); 146.8(s); 140.9(s); 124.0(d);123.5(d); 120.4(d); 61.6(t); 41.6(d); 38.0(t); 34.6(s); 32.5(t);31.6(3q); 30.9(t) δ ppm.

MS: 218(60), 203(100), 185(29), 173(84), 161(84), 157(52), 143(84),129(60), 117(70), 91(22), 77(10), 57(50).

EXAMPLE 13

Preparation of 3-(5-indanyl)-1-propanal and 3-(4-indanyl)-1-propanal

Prepared by hydrolysis of (E)-3-(5-indanyl)-1-propenyl acetate [3.3 g;13.6 mmole; 89% pure mixture containing 74% of this compound and 15% of(E)-3-(4-indanyl)-1-propenyl acetate], by means of 25% sulfuric acid (6ml) in THF (25 ml), in an analogous manner to that described inExample 1. After 4 h of reflux and the treatment described, bulb-to-bulbdistillation (125°/10 Pa) provided 2.07 g of a product having a purityof 99% and containing 83% of 3-(5-indanyl)-1-propanal and 16% of3-(4-indanyl)-1-propanal (yield 87%).

Analytical characters:

IR(neat): 2950, 2840, 2710, 1720, 1490, 1435, 1060, 820 cm⁻¹.

Major isomer:

NMR(¹ H, 360 MHz, CDCl₃): 9.78(d, J=1.5 Hz, CHO); 7.13(d, J=8 Hz, 1H);7.05(s, 1H); 6.94(d, J=8 Hz, 1H); 2.91(t, J=8 Hz, 2H); 2.87(t, J=7 Hz,2H); 2.86(t, J=7 Hz, 2H); 2.73(dt, J=1.5, 8 Hz, 2H); 2.05(quint, J=7 Hz,2H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 201.8(s); 144.7(s); 142.2(s); 138.1(s);126.1(d); 124.4(d); 124.3(d); 45.6(t); 32.8(t); 32.4(t); 28.0(t);25.5(t) δ ppm.

MS: 174(73), 156(3), 145(14), 131(76), 128(33), 118(100), 103(7),91(37), 77(12), 65(8), 63(9), 51(9), 39(10), 29(14).

Odor: described above.

The starting acetate was prepared thus:

In a 200 ml three-neck flask, 6.4 g of indane (Fluka purum 95%, 50mmole) are dissolved in 50 ml of CH₂ Cl₂ puriss, then add dropwise andquickly at room temperature 6.0 ml of TiCl₄ (Fluka, 55 mmole; 1.1 eq)then 0.12 ml of BF₃.Et₂ O (Fluka 48%, 1 mmole; 0.02 eq). After stirringat room temperature during 30 min, the solution is cooled to -10°, thena solution of 7.9 g of acrolein diacetylacetal (Fluka 98%, 50 mmole)dissolved in 20 ml of CH₂ Cl₂ is added thereto dropwise in 30 min. Afterstirring the solution during 1 h at -5°, the reaction mixture is pouredon a mixture of ice and 10% HCl, then extracted with ether. The etherphase is then washed with brine until neutral pH, then dried over Na₂SO₄ and concentrated under vacuum. There were obtained 10.9 g of a brownliquid which was bulb-to-bulb distilled (185°/10 Pa) to provide 4.51 gof a product containing 74.0% of (E)-3-(5-indanyl)-1-propenyl acetateand 15.0% of (E)-3-(4-indanyl)-1-propenyl acetate (yield 37,0%).

IR(neat): 2960, 2840, 1755, 1670, 1430, 1370, 1225, 1100, 940, 900 cm⁻¹.

The following data are for the major isomer:

NMR(¹ H, 360 MHz, CDCl₃): 7.17(dt, J=12, 1 Hz, 1H); 7.13(d, J=7 Hz, 1H);7.05(s, 1H); 6.95(d, J=7 Hz, 1H); 5.57(dt, J=12, 8 Hz, 1H); 3.28(d, J=82H); 2.86(t, J=7 Hz, 4H); 2.1(s, 3H); 2.05(m, 2H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 168.2(s); 144.6(s); 142.2(s); 137.5(s);136.1(d); 126.2(d); 124.3(2d); 114.2(d); 33.4(t); 32.8(t); 32.5(t);25.5(t); 20.7(q) δ ppm.

MS: 216(47), 174(65), 156(15), 145(28), 131(44), 118(89), 91 55(7),43(100), 39(7).

EXAMPLE 14

Preparation of 3-(5-indanyl)-2-methyl-1-propanal

Prepared by hydrolysis of (E)-3-(5-indanyl)-2-methyl-1-propenyl acetate[4 g, 17.4 mmole; 96% pure mixture containing 84.1% of this compound and11.7% of (E)-3-(4-indanyl)-2-methyl-1-propenyl acetate], by means of 10ml of 25% sulfuric acid and in 50 ml of THF, in an analogous manner tothat described in the previous example. After treatment and bulb-to-bulbdistillation (110°/15 Pa) there were obtained 2.81 g of a 96% pureproduct, containing 3-(5-indanyl)-2-methyl-1-propanal and3-(4-indanyl)-2-methyl-1-propanal in a 9:1 ratio (yield 82.4%).

Analytical characters:

IR(neat): 2940, 2860, 2700, 1750, 1500, 1450, 915, 835, 800 cm⁻¹.

Major isomer:

NMR(¹ H, 360 MHz, CDCl₃): 9.71(d, J=2 Hz, CHO); 7.13(d, J=8 Hz, 1H);7.03(s, 1H); 6.93(d, J=8 Hz, 1H); 3.03(dd, J=13, 5 Hz, 1H); 2.86(t,J=7.5 Hz, 4H 2.63(m, 1H); 2.57(dd, J=13, 8 Hz, 1H); 2.05(quint, J=7.5Hz, 2H); 1.08(d, J=8 Hz, 3H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 204.6(d); 144.6(s); 142.3(s); 136.5(s);126.8(d); 125.0(d); 124.3(d); 48.3(d); 36.6(t); 32.8(t); 32.5(t);25.5(t); 13.3(q) δ ppm.

MS: 188(31), 173(2), 160(4), 145(5), 131(100), 128(15), 118(28),115(24), 91(20), 77(6), 29(8).

Odor: citrus, metallic, citronellal.

The starting acetal is prepared thus:

In a 200 ml three-neck flask, 6.5 ml of indane (Fluka purum 95%, 50mmole) are dissolved in 40 ml of CH₂ Cl₂ puriss, then add dropwise andquickly at room temperature 6.0 ml of TiCl₄ (Fluka, 55 mmole; 1.1 eq)then 0.39 ml of BF₃.Et₂ O (Fluka 48%, 1.5 mmole; 0.03 eq). Afterstirring at room temperature during 30 min, the solution is cooled to-10°, then a solution of 9.22 ml of methacrolein diacetylacetal (Fluka98%, 50 mmole) dissolved in 25 ml of CH₂ Cl₂ is added thereto dropwisein 30 min. After stirring the solution during 1 h at -5°, the reactionmixture is poured on a mixture of ice and 10% HCl, then extracted withether. The ether phase is then washed with brine until neutral pH, thendried over Na₂ SO₄ and concentrated under vacuum. There were obtained11.2 g of a brown liquid which was bulb-to-bulb distilled (140°/15 Pa)to provide 4.18 g of a product containing 84.1% of(E)-3-(5-indanyl)-2-methyl-1-propenyl acetate and 11.7% of(E)-3-(4-indanyl)-2-methyl-1-propenyl acetate (yield 34.7%).

IR(neat) : 2942, 1752, 1490, 1369, 1228, 1099, 921, 813 cm⁻¹.

Major isomer:

NMR(¹ H, 360 MHz, CDCl₃): 7.13(d, J=8 Hz, 1H); 7.04(s, 2H); 6.94(d, J=8Hz, 1H); 3.21(s, 2H); 2.86(t, J=7.5 Hz, 4H); 2.13(s, 3H); 2.05(quint,J=7.5 Hz, 2H; 1.6(d, J=2 Hz, 3H) δ ppm.

NMR(¹³ C, 90.5 MHz, CDCl₃): 168.3(s); 144.5(s); 142.2(s); 136.7(s);131.1(d); 126.6(d); 124.7(d); 124.2(d); 121.5(s); 40.2(t); 32.8(t);32.5(t); 25.5(t); 20.8(q); 13.6(q) δ ppm.

MS: 230(32), 188(53), 170(10), 160(10), 155(7), 145(11), 131(73),118(100), 91(21), 77(6), 43(59).

EXAMPLE 15

Preparation of a Perfuming Composition

A base perfuming composition intended for a feminin type perfume wasprepared by admixing the following ingredients:

    ______________________________________                                        Ingredients          Parts by weight                                          ______________________________________                                        Benzyl acetate       15                                                       Geranyl acetate       8                                                       Linalyl acetate      35                                                       Styrallyl acetate     4                                                       10%* Cinnamic alcohol                                                                               6                                                       10%* Anisic aldehyde  5                                                       Cyclosia ® Base.sup.1)                                                                          7                                                       10%* Damascenone     15                                                       10% β-Dorinone ®.sup.2) in ethyl citrate                                                  12                                                       Ethyl linalol        20                                                       Eugenol              25                                                       Exaltolide ®.sup.3)                                                                            17                                                       Galaxolide ®.sup.4) 50                                                                         55                                                       Hedione ®.sup.5) 60                                                       Heliotropine         44                                                       10%* Hexylix ®.sup.6)                                                                          20                                                       10% Indol in triethylamine                                                                         32                                                       Iso E Super.sup.7)   100                                                      Levocitrol           24                                                       Linalol              20                                                       Phenethylol           5                                                       10%* Polysantol ®.sup.8)                                                                       60                                                       Polywood ®.sup.9) Super                                                                        15                                                       Benzyl salicylate    110                                                      Pipol salicylate     30                                                       10%* Tagetes essential oil                                                                         12                                                       α-Terpineol    45                                                       10%* Vanilline        8                                                       α-Ionone       14                                                       β-Ionone        52                                                       Dianthine ®.sup.10) SA                                                                          5                                                       Total                880                                                      ______________________________________                                         *in dipropyleneglycol (DIPG)                                                  .sup.1) hydroxycitronellal based mixture; origin: Firmenich SA, Geneva,       Switzerland                                                                   .sup.2) 1(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-buten-1-one; origin:           Firmenich SA, Geneva, Switzerland                                             .sup.3) pentadecanolide; origin: Firmenich SA, Geneva, Switzerland            .sup.4)                                                                       1,3,4,6,7,8hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-g-2-benzopyrane;       origin: International Flavors & Fragrances Inc., USA                          .sup.5) methyl dihydrojasmonate; origin: Firmenich SA, Geneva, Switzerlan     .sup.6) allyl (cyclohexyloxy) acetate; origin: Charabot, France               .sup.7) 1(octahydro-2,3,8,8-tetramethyl-2-naphtalenyl)-1-ethanone; origin     International Flavors & Fragrances Inc., USA                                  .sup.8) 3,3dimethyl-5-(2,2,3-trimethyl-3-cyclopenten-1-yl)-4-penten-2-ol;     origin: Firmenich SA, Geneva, Switzerland                                     .sup.9) perhydro5,5,8atrimethyl-2-naphtalenyl acetate; origin: Firmenich      SA, Geneva, Switzerland                                                       .sup.10) origin: Firmenich SA, Geneva, Switzerland                       

To this base composition of the floral, green type, there were added, onthe one hand 120 parts by weight of3-(5-tert-butyl-2-methyl-1-phenyl)propanal according to the invention toprepare a novel composition A and, on the other hand, 120 parts byweight of 3-(4-tert-butyl-1-phenyl)-2-methylpropanal, or LILIAL®, toprepare a composition B. The two compositions were then evaluated on ablind test by a panel of 13 expert perfumers. According to the unanimousopinion of the latter, novel composition A was preferred for its muchsofter and natural floral note, relative to that of composition B. Theperfumers also judged that the odor of composition A was more powerfuland voluminous, its fragrance appearing as far more powdery, the jasmineand lily of the valley characters being distinctly exhalted. When therewere added to the base composition 120 parts by weight of2-(5-tert-butyl-2-methylbenzyl)propanal according to the invention,there was obtained a novel composition C, the odor of which was verysimilar to that of composition A, the floral note being neverthelessaccompanied by a greener character.

EXAMPLE 16

Preparation of a Perfuming Composition

A base perfuming composition intended for a powder detergent wasprepared by admixing the following ingredients:

    ______________________________________                                        Ingredients              Parts by weight                                      ______________________________________                                        Carbinol acetate         15                                                   Linalyl acetate          30                                                   (3 and 4)-(4-methyl-3-penten-1-yl)-3-cyclohexene-                                                      20                                                   3-carbaldehyde                                                                Amylcinnamic aldehyde    125                                                  50%* Undecylenic aldehyde                                                                              15                                                   50%* Methyl nonyl aldehyde                                                                             15                                                   Citronellol              15                                                   Dihydromyrcenol ®.sup.1)                                                                           15                                                   10%* Exaltolide ®.sup.2)                                                                           30                                                   Geraniol brut            30                                                   Heliotropine             15                                                   Iralia ®.sup.3)      90                                                   Linalol                  25                                                   Lorysia ®.sup.4)     110                                                  Methyl methylanthranilate                                                                               5                                                   Patchouli essential oil  30                                                   Phenylhexanol            25                                                   Polysantol ®.sup.5)  20                                                   Polywood ®.sup.6) Super                                                                            10                                                   Spiranol.sup.7)          10                                                   Terpineol                50                                                   Tonalid ®.sup.8)     70                                                   Phenylacetaldehyde dimethylacetal                                                                      10                                                   Vertofix coeur.sup.9)    40                                                   Dorinia SA.sup.10)       20                                                   Galbex ®.sup.11) 183 10                                                   Total                    850                                                  ______________________________________                                         *in DIPG                                                                      .sup.1) 2,6dimethyl-7-octen-2-ol; origin: International Flavors &             Fragrances Inc., USA                                                          .sup.2) see example 3                                                         .sup.3) methylionone (isomer mixture); origin: Firmenich SA, Geneva,          Switzerland                                                                   .sup.4) 4(1,1-dimethylethyl)-1-cyclohexyl acetate; origin: Firmenich SA,      Geneva, Switzerland                                                           .sup.5) see example 3                                                         .sup.6) see example 3                                                         .sup.7) 2,6,10,10tetramethyl-1-oxaspiro[4.5]decan6-ol; origin: Firmenich      SA, Geneva, Switzerland                                                       .sup.8) (5,6,7,8tetrahydro-3,5,5,6,8,8-hexamethyl-2-naphthyl)-1-ethanone;     origin: PFW, Holland                                                          .sup.9) origin: International Flavors & Fragrances Inc., USA                  .sup.10) origin: Firmenich SA, Geneva, Switzerland                            .sup.11) origin: Firmenich SA, Geneva, Switzerland                       

To this base composition of the floral type there were added 150 partsby weight of 5-tert-butyl-1-indancarbaldehyde to prepare a novelcomposition A and 150 parts by weight of3-(4tert-butyl-1-phenyl)-2-methylpropanal, or BOURGEONAL®, to prepare acomposition B. These two compositions were then used in identicalconcentrations to prepare two samples, respectively A and B, of aperfumed powder detergent. A panel of 7 perfumers, evaluating these twodetergent samples on a blind test showed a clear preference for sampleA, the odor of which was judged stronger and more elegant than that ofsample B. Two standard batches of textiles were then washed separatelyin two washing machines with the samples A and B and the odor of thetextiles was evaluated on a blind test by a panel of six expertperfumers. The evaluation was carried out with the wet textiles, justout of the machine, as well as after 24 h of drying in air. Theperfumers unanimously preferred the odor of the textiles treated withsample A, both wet and after drying. The odor of this batch of textileswas judged distinctly superior, both in strength and quality, to that ofthe textiles washed with sample B. The odor of the wet linen washed withsample A was judged much more floral than that of the textiles treatedwith sample B, whereas the dry textiles developed a much stronger odor,which odor also remained on the textiles for a far longer period of timethan that of the textiles treated with sample B.

EXAMPLE 17

Stability Test on Smelling-Strip

Stability tests on smelling strip were carried out by comparing theperformance of certain compounds of the invention, i. e.3-(5-tert-butyl-2-methyl-1-phenyl)-1-propanal (smelling strip A),3-(5-tert-butyl-2-methylbenzyl)-1-propanal (smelling strip B),5-tert-butyl-2-indancarbaldehyde (smelling strip C) and3-(3,3-dimethyl-5-indanyl)-1-propanal (smelling strip F), with that oftheir two known analogues, i.e. 3-(4tert-butyl-1-phenyl)propanal orBOURGEONAL® (smelling strip D) and3-(4-tert-butyl-1-phenyl)-2-methylpropanal or LILIAL® (smelling stripE). Thus, a panel of 4 expert perfumers dipped the smelling strips intovials containing the above-mentioned compounds in a pure form, so as toobtain a soaked zone of about 1 cm in each case. These smelling stripswere then evaluated on a blind test and their odors compared over time,this operation having been repeated every day, until the perfumers couldno longer detect any odor from any of the smelling strips. In theiropinion, at the begining of the test, smelling strips A and B developedfloral odors wherein the lily of the valley type connotation wasdistinctly dominant. In addition, smelling strip A developed a notewhich was reminiscent of the odor of thyme. As for smelling strip C, itdeveloped a remarkably powerful floral note, with a greener characterwhich was closer to the odor of BOURGEONAL®. Smelling strip D had a fargreener and aldehydic floral odor than that of smelling strips A and B,also more agressive, and smelling strip E had a floral odor of the sametype as that of smelling strips A and B, but wherein the lily of thevalley character was distinctly more marked. Finally, smelling strip Pdeveloped a floral odor wherein the green connotation was very strong,such that it reminded one of the odor of freshly washed linen. Theevolution in time of the odor intensity of the six smelling strips, asjudged by the perfumers on a value scale of 0 to 10, is indicated in thefollowing table:

    ______________________________________                                        Smelling                                                                      strip     3 days  7 d     9 d 12 d   15 d 20 d                                ______________________________________                                        A         7       3       --  --     --   --                                  B         6       --      --  --     --   --                                  C         5       5       5   4      4    3                                   D         8       4       --  1      --   --                                  E         --      --      --  --     --   --                                  F         7       --      6   4      4    3                                   ______________________________________                                    

Thus, it was observed that smelling strips A and B, which at thebegining developed odors close to that of smelling strip E, and at leastas strong, kept this odor for about 5 days, whereas the odor of smellingstrip E decreased strongly in the first 24 h and could no longer bedetected at the end of 3 days. On the other hand, smelling strip D kepta strong odor at the end of 3 days, which however abated rapidly withinthe following week, whereas smelling strip C, whose odor intensity wasat the begining inferior to that of smelling strip D, but similar, kepthenceforth a practically stable intensity and still developed aperfectly perceptible fragrance 20 days after having been dipped in5-tert-butyl-2-indancarbaldehyde according to the invention.Furthermore, according to the perfumers, the quality of the odor ofsmelling strip C had suffered no deterioration whatsoever at the end ofthis period. Similar behaviour was observed with smelling strip F whichconserved its odor for more than a month, thus revealing the remarkabletenacity of the 3-(3,3 dimethyl-5-indanyl)-1-propanal according to theinvention.

EXAMPLE 18

Test of Stability Against Oxidation by Gas Phase Chromatography (GC)

The qualitative evolution described in the preceding example for3-(5-tert-butyl-2-methyl-1-phenyl)-1-propanal and its prior artanalogues, on the basis of the perfumers' odor evaluation, was entirelyconfirmed, in a quantitative manner, by means of gas phasechromatography (CC) measurements. The following method was applied.

Onto standard smelling strips (7×47 mm) there was deposited a drop ofrespectively 3-(5-tert-butyl-2-methyl-1-phenyl)-1-propanal (smellingstrip A), 3-(4-tert-butyl-1-phenyl)propanal or BOURGEONAL® (smellingstrip B) and of 3-(4-tert-butyl-1-phenyl)-2-methylpropanal or LILIAL®(smelling strip C). The thus soaked zone of the smelling strips (˜20 mm)was cut and immersed for 1 h in CH₂ Cl₂ (1 ml) contained in closed testtubes, with occasional stirring. Before injecting the solutions in a GCapparatus, bis-(trimethylsilyl)-acetamide (Aldrich, 4 drops, ˜30 mg) wasadded to each of the three solutions, to form the trimethylsilylic esterof the acid into which the aldehyde extracted from each of the smellingstrips had been converted by air oxidation. It had in fact been observedthat the GC signal of said esters was distinctly less broad than that ofthe corresponding adds, thus allowing a far more precise integration.The three solutions were then injected into a GC apparatus (SiO₂, 10 mcolumn) at regular time intervals, adapted to the oxidation speedobserved for each of the three above-mentioned aldehydes. The signalscorresponding to the aldehyde and the trimethylsilyl ester (the latterbeing proportional to the amount of formed acid) were integrated and theresults obtained represented on the graph of FIG. 1. On this graph, thepercentage of aldehyde and corresponding acid are represented as afunction of time. The curves represented translate the average valuesobtained in two distinct experiments, carried out with each of thecompounds whose structures are represented. It is clearly apparent fromFIG. 1 that the compound according to the invention, i. e.3-(5-tert-butyl-2-methyl-1-phenyl)-1-propanal, is far more stableagainst air oxidation than its known isomer3-(4tert-butyl-1-phenyl)-2-methylpropanal or LILIAL®, which, at the endof about 4 days, has been converted to the extent of 80% into thecorresponding acid, which is practically odorless. When comparing thecompound of the invention with its known lower homologue, i. e. the3-(4-tert-butyl-1-phenyl)propanal or BOURGEONAL® (origin: Naarden Int.,Holland), again it can be clearly seen that the latter, although farmore stable than LILIAL®, has been converted up to 70% into thecorresponding acid at the end of about 20 days, whereas the aldehydeaccording to the present invention is still ˜60% stable. Analogous testswere carried out with another compound of the invention, i.e.3-(3,3-dimethyl-5-indanyl)-1-propanal, and the results, represented inFIG. 2, also show that this compound is more stable against oxidationthan the two known compounds cited above. It should be noted that theseresults cannot be imputed to differences in volatility and/or polarityof the compounds of the invention relative to their known analoguesLILIAL® and BOURGEONAL®. We have in fact measured the retention times ofthese two compounds in two types of (GC) columns (100--20°, 10°/min),and the results presented hereinafter show that there are no significantdifferences in these values.

    __________________________________________________________________________                            3-(5-tert-butyl-2-                                                                    3-(3,3-dimethyl-5-                            Retention time GC       methyl-1                                                                              indanyl)propanol                              [min]     LILIAL ®                                                                       BOURGEONAL ®                                                                       phenyl)propanol                                                                       (2 isomers)                                   __________________________________________________________________________    Silica column (10 m)                                                                    4.01 4.10     4.34    5.03;5.17                                     Carbowax column                                                                         5.62 5.69     6.78    6.46;6.80                                     (10 m)                                                                        __________________________________________________________________________

EXAMPLE 19

Perfuming Composition for a Powder Detergent

A base perfuming composition intended for a powder detergent wasprepared by admixture of the following ingredients:

    ______________________________________                                        Ingredients         Parts by weight                                           ______________________________________                                        Benzyl acetate      200                                                       Linalyl acetate     70                                                        Verdyl acetate      160                                                       Anisic aldehyde     60                                                        10%* Decanal        10                                                        Hexylcinnamic aldehyde                                                                            300                                                       10%* Methylnonyl aldehyde                                                                         10                                                        Methyl anthranilate 25                                                        Astrotone.sup.1)    150                                                       Coranol.sup.2)3)    50                                                        Allyl cyclohexylpropanoate                                                                        10                                                        10%* Ethylvanilline 70                                                        Hedione ®.sup.3)4)                                                                            100                                                       Heliotropine        25                                                        Galaxolide 50.sup.5)6)                                                                            380                                                       Iralia ® Total.sup.3)7)                                                                       600                                                       Iso B Super.sup.5)8)                                                                              250                                                       Koavone.sup.5)9)    70                                                        Methylnaphthylketone                                                                              10                                                        p-tert-Butylcyclohexanone acetate                                                                 250                                                       Phenylhexanol       30                                                        Verdyl propanoate   100                                                       Amyl salicylate     60                                                        Galbex ®183.sup.3)                                                                            10                                                        Total               3000                                                      ______________________________________                                         *in DIPG                                                                      .sup.1) ethylene undecane dicarboxylate                                       .sup.2) 4cyclohexyl-2-methyl-2-butanol                                        .sup.3) origin: Firmenich SA, Geneva, Switzerland                             .sup.4) methyl 3oxo-2-pentyl-cyclopentylacetate                               .sup.5) origin: International Flavors & Fragrances Inc., USA                  .sup.6)                                                                       1,3,4,6,7,8hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-g-2-benzopyrane        .sup.7) isomethyl-ionone                                                      .sup.8) 7acetyl-1,2,3,4,5,6,7,8-octahydro-1,1,6,7-tetramethyl-naphthalene     .sup.9) acetyldiisoamylene                                               

When there are added to 30 parts by weight of the composition thusobtained 3 parts by weight of 3-(3,3-dimethyl-5-indanyl)-1-propanal,there is obtained a novel composition having a distinctly enhanced greennote. In addition, the composition acquires a marked fresh character.Such an olfactive note was as well developed in a powder detergent, asin the wet linen washed with the detergent perfumed by means of saidnovel composition. Once dried, the linen (after 24 h) had a typicalaldehydic, green fresh odor, which instantly aroused in the user apleasant sensation of very dean linen. Upon adding to the basecomposition the same proportion of 5-tert-butyl-2-indancarbaldehyde anolfactive effect similar to that described above was obtained, albeitslightly less powerful, whereas the addition of the same amount of6-tert-butyl-1-indanacetaldehyde imparted to the composition a morepronounced odor of the green-leafy type, wherein the aldehydic-lily ofthe valley character was not as perceptible as in the case of theaddition of the two compounds above-cited.

EXAMPLE 20

Perfuming Base

A base composition of the floral, woody type, intended for a soap, wasprepared by admixing the following ingredients:

    ______________________________________                                        Ingredients         Parts by weight                                           ______________________________________                                        Benzyl acetate      250                                                       Citronellyl acetate 150                                                       Phenylethyl acetate 120                                                       Styrallyl acetate   100                                                       Anisic aldehyde     100                                                       50%* Undecylenic aldehyde                                                                         120                                                       Hexylcinnamic aldehyde                                                                            200                                                       4-(4-hydroxy-1-phenyl)-2-butanone                                                                  5                                                        Citronellol          51                                                       Dihydromyrcenol.sup.1)5)                                                                          200                                                       10%* Ethylvanilline  30                                                       Eugenol              60                                                       Lilial ®.sup.2) 120                                                       Hedione ®.sup.3)4)                                                                            100                                                       10%* Methyl-p-cresol                                                                               40                                                       Vertofix coeur.sup.5)                                                                             430                                                       Iralia ® Total.sup.3)6)                                                                       130                                                       γUndecalactone                                                                               5                                                        Phenethylol         300                                                       Phenylhexyl phenylacetate                                                                          20                                                       p-tert-Butylcyclohexanone acetate                                                                 750                                                       Polysantol ®.sup.1)3)                                                                          20                                                       Verdyl propanoate   250                                                       Hexyl salicylate    400                                                       Tonalid ®.sup.1)                                                                              100                                                       Violet essential oil                                                                               20                                                       Ylang synth.         50                                                       Total               4220                                                      ______________________________________                                         *in DIPG                                                                      .sup.1) see example 16                                                        .sup.2) origin: GivaudanRoure, Vernier, Switzerland                           .sup.3) origin: Firmenich SA, Geneva, Switzerland                             .sup.4) methyl 3oxo-2-pentylcyclopentylacetate                                .sup.5) origin: International Flavors & Fragrances Inc., USA                  .sup.6) isomethylionone                                                  

The addition, to this base composition, of 80 parts by weight of6-tert-butyl-1-indanacetaldehyde imparted thereto an aldehydic-greennote that recalled the olfactive effect that one can achieve withBOURGEONAL®, whereas adding the same amount of5-tert-butyl-2-indancarbaldehyde or of3-(3,3-dimethyl-5-indanyl)-1-propanal produced a clearly distinctfloral-lily of the valley effect, all the more powerful in the lattercase. This latter compound also imparted to the base composition, in amore marked manner, a pleasant fresh, clean linen character.

What we claim is:
 1. A compound of formula ##STR35## wherein thetert-butyl radical is located in positions 5 or 6 of the aromatic ringand either (1) Y represents hydrogen; X represents a --CHO group or agroup of formula ##STR36## in which symbols R', taken separately, eachrepresent a C₁ to C₄ linear or branched, saturated or unsaturated alkylradical, or taken together represent a substituted or unsubstituted C₂to C₄ alkylene radical; and R² represents a hydrogen atom or a methylradical; or (2) X and R² each represent a hydrogen atom and Y representsa --CH₂ CHO group or a group of formula ##STR37## in which symbols R'are as defined above.
 2. The compound of claim 1 selected from the groupconsisting of:5-tert-butyl-2-indancarbaldehyde;5-tert-butyl-2-methyl-2-indancarbaldehyde; and6-tert-butyl-1-indanacetaldehyde; and2-(5-tert-butyl-2-indanyl-1,3-dioxolane.
 3. A method to confer, improve,enhance or modify the odor properties of a perfuming composition or aperfumed article, which method comprises adding to said composition orarticle a fragrance effective amount of a compound according to claim 1.4. A method to confer, improve, enhance or modify the odor properties ofa perfuming composition or a perfumed article, which method comprisesadding to said composition or article a fragrance effective amount of acompound according to claim
 2. 5. A perfuming composition or a perfumedarticle which contains as an active perfuming ingredient a compoundaccording to claim
 7. 6. A perfuming composition or a perfumed articlewhich contains as an active perfuming ingredient a compound according toclaim
 2. 7. A perfumed article according to claim 5, in the form of aperfume, a cologne, a soap, a bath or shower gel, a shampoo or otherhair-care product, a cosmetic preparation, a body deodorant or anair-freshener, a detergent or a fabric softener, or a household product.8. A perfumed article according to claim 6, in the form of a perfume, acologne, a soap, a bath or shower gel, a shampoo or other hair-careproduct, a cosmetic preparation, a body deodorant or an air-freshener, adetergent or a fabric softener, or a household product.
 9. A process forthe preparation of a compound of formula ##STR38## wherein thetert-butyl radical is located in position 5 or 6 of the aromatic ringand either Y represents hydrogen and X and R² are defined as in formula(Ia), or X and R² represent hydrogen and Y represents a --CH₂ CHO or agroup of formula ##STR39## in which R' has the meaning indicated informula (Ia), which process comprises:a. treating with an oxidizingagent an alcohol of formula ##STR40## to form the corresponding aldehyde(Ib); b. where applicable, methylating, in a generally known manner, thealdehyde obtained in a. which corresponds to alcohol (IVb) to form analdehyde (Ib) of formula ##STR41## and c. where applicable, acetalizing,in a generally known manner, said aldehyde (Ib) to form thecorresponding acetal.
 10. A compound of formula ##STR42## wherein thetert-butyl radical is located in position 5 or 6 of the aromatic ring,or of formula ##STR43##